I recommend starting with Stormlight, but if you want to fully understand it, you should probably read the first Mistborn book before Rhythm of War and Warbreaker before Oathbringer (Warbreaker is probably my second-favourite Sanderson book, due to its "wholesomeness"). You should also read the novellas as you get through Stormlight, but I believe Dawnshard has far more more plot significance than Edgedancer. Mistborn is pretty good, but it's not as meaningful or deep as Stormlight.